It has to be about the only thing in terms of measurements or numbers in which the American way of doing it makes more sense. Where in America the beginning of the word ("bi-llion", "tri-llion", "quadri-llion",...) indicates the amount of times the number is multiplied by 1000 starting from 1 million, the "long scale" is different because it has two words at every level: a thousand million is a milliard, and only a million million is a billion. However, the result is that in long scale, the bi-, tri-,... part indicates how many times the number is multiplied by 1 million, also starting from 1 million, which isn't so illogical either.

Bottom line is just that it's annoying the two systems exist and you have to watch out in every new language you learn which of the two it uses. It's unfortunately not as simple as "English uses short scale, every other language long scale".